Filters of the type used for filtering particulate matter from fluid sometimes include a filter housing having an inlet for receiving the fluid with entrained particulate matter, and an outlet for delivering the filtered fluid to a device needing fluid that is free of particulate matter. For example, a filter may be provided at the air inlet of an internal combustion engine. An example of such a filter is provided in U.S. Pat. No. 7,828,869 to Parikh et al.
In such filters, the particulate matter is typically removed by a filter element that is installed within the filter housing in such a manner that the fluid must flow through the filter element, including a filter pack of porous filter material, which removes the particulate matter from the fluid. One such filter element is a coalescer filter element that includes a coalescer filter pack. A coalescer filter pack operates by capturing the denser particulate matter of a contaminated fluid including at least two constituents, such as air and oil, fuel and water, or water and oil. In the case of air and oil, the coalescer filter pack captures the denser oil, coalesces the oil, and passes the less dense air. An example of such a coalescer filter pack is provided in U.S. Pat. No. 8,114,183 to Schwandt et al.
Over time, the coalescer filter pack of the coalescer filter element will become plugged or coated with particulate matter, necessitating removal and replacement of the filter element in order for the filter to continue in its function of supplying particulate-free fluid at the outlet of the housing. As such, a tradeoff made in designing a coalescer filter element is removal efficiency of the denser portion of the contaminated fluid and lifetime of the coalescer filter pack versus size of the coalescer filter pack.
It is desirable to provide an improved coalescer filter element having a coalescer filter pack that is more robust than the arrangements used in prior filters. It is also desirable to provide such an improved filter element and filter apparatus in a form that can be manufactured in a straight-forward and low cost manner.
The invention provides such a filter. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.